Process for the protection of the surface of baths of easily-oxidizable metals such as magnesium



Patented July 9, 1929.

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FATE

GILBERT Mrcnnn or BAGNEUX, FRANCE.

PROCESS FOR THE PROTECTION OF- ;mE SURFACE .01? BATHS or EASILY-OXIDIZABLE METALS soon as MAGNESIUM.

No Drawing. Application filed August 2, 1926,.Serial No. 126,727, and in France August 18, 1925.

Application-for French patent has been filed on Aug. 18, 1925, and for'British patent has been filed on Feb. 10, 1926. a

The present invention has for its object a process for the protection of the surface of baths of easily .oxidizable metals consisting essentially in distributing sulphur, not directly upon the metallic surface, but upon a layer of a protective substance which itself forms a protecting crust, such for instance as the fluoride of the metal under consideration.

; Itthus embraces the employment, of magnesium fluoride, for forming the protective crust on a bath of molten magnesium.

The invention may be carried into effect by way of example in the following manner inby the addition the case of molten magnesium.

A protective crust of magnesium fluoride is formed on the surface of the molten metal. This constitutes a solid crust which floats on the surface and constitutes in itself a good protection for the metal. Pulverulent sulphur is then sprinkledupon the protecting layer where it melts and burns slowly, since the crust of fluoride has a much lower temperature than the molten metal and obviously the crust is not a good conductor of heat. 1 a

On account of this the evolution of 5111-. phurous gas becomes so slow that the operator. is not incommoded thereby and, in addition,- direct contact of the sulphur with the metal being avoided, the formation of sulphides and oxy-sulphides need not be feared.

It must be understood that the protective layer of magnesiumfluoride may be replaced by other fluorides or even chlorides. It may,

- sium inthe form of a crust for the protection of light metals, both With and without the creation of a neutral surrounding atmosphere '5 of sulphur.

I claim: n l. A method of protecting the surface of a bath of easily oxidizable metal which consists in covering the free surface of the bath with a protective layer and covering the crust so formed with sulphur.

2. A. method of protecting the surface of. a bath of easily oxidizable metal Which consists in covering the free surface of the bath with a protective layer ofthe fluoride of the said metal and covering the crust so formed with sulphur. 3. A method of protecting the surface of a bath of molten magnesium, which consists in 7 covering; the free surface of the bath with a protective layer of magnesium fluoride, and covering the crust so formed with sulphur.

In testimonywvhereof I'afiix my signature.

GILBERTMICHEL. 

